Oriental Powder Company was a gunpowder manufacturer with mills located on the Presumpscot River in Gorham and Windham, Maine.
Sebago Lake formed a large natural reservoir upstream of Gambo giving the falls an unusually reliable water supply with comparatively minor flow peaking from storm runoff.
When Lester came east to Maine, his first cousins traveled west to build gunpowder mills in New York and Chicago.
[4] Following an explosion killing seven employees on 19 July 1828,[5] the Gambo Falls mill was enlarged by Oliver Whipple concurrently with construction of locks for the Cumberland and Oxford Canal.
The new canal provided reliable transportation from Portland harbor for sulfur from Sicily and saltpeter from India and from Sebago Lake for charcoal and lumber from forests to the north.
Moist saltpeter crystals were mixed with appropriate amounts of sulfur and charcoal by heavy rotating wheels to form a cake which was then cut unto smaller pieces in bronze- or zinc-toothed kernelling mills.
The kernels were sieved into desired sizes and dried prior to being tumbled with graphite which reduced tendency for the finished grains to stick together during storage.
The larger DuPont and Hazard Powder Company mills each provided approximately one-third of the Union gunpowder supply for the civil war.
[3] The DuPont mill was uncomfortably close to the battle line and considered potentially vulnerable to sabotage from southern sympathizers in the slave state of Delaware.
The Newhall mill ceased operations on 1 June 1893 as smokeless powder and dynamite became preferred for traditional uses of gunpowder.
[5] Mill operations after the 1904 explosion were limited to manufacturing wood flour shipped elsewhere for mixing with nitroglycerine to form dynamite.